Why does glue contain formaldehyde?

Formaldehyde mainly exists in the urea-formaldehyde resin-based adhesive, furniture using the board mainly includes density board, particle board, plywood and other man-made panels. The process of manufacturing such panels is simple: the wood is processed into wood chips, and then add adhesives, through high temperature extrusion and other ways, the wood chips processed into panels. And formaldehyde is present in the adhesive.

By mixing urea and formaldehyde together and polymerizing them under the catalyst of acid or alkali, the traditional process adds 1.5 to 2 times the amount of formaldehyde to ensure product grade. Because of the viscosity of the urea-formaldehyde resin, so after the reaction there will be a large number of unreacted formaldehyde mixed in the whole system, is to cause the decoration of the formaldehyde hazard of free formaldehyde.

You may have such a question: formaldehyde is so harmful, do not use urea-formaldehyde resin glue is not on the line? Use other instead of can not? This is now the green chemistry and chemical industry for formaldehyde pollution in the decoration of the direction of efforts - urea-formaldehyde resin glue substitutes, but at present there is not too good results.

1, the most critical reason, the production cost of urea-formaldehyde resin is very cheap.

Not only the raw materials - urea and formaldehyde, the two basic chemical products are quite cheap, and urea-formaldehyde resin has formed a mature industrial chain. And the traditional industry inertia is also a big problem, but recognized a certain production process, want to realize in a short period of time to turn more difficult. Other products want to compete with urea-formaldehyde resin, from the cost is very difficult, new products and urea-formaldehyde resin compared to the cost of tens or even hundreds of times higher.

2, the second formaldehyde as an adhesive performance is not bad.

The most traditional three aldehyde-containing resins: urea-formaldehyde resins, phenolic resins and melamine - formaldehyde resins, and the color of urea-formaldehyde resins is the lightest (phenolic resins cured color is darker, lighter color which is very important for the decoration of adhesives), and no curing of urea-formaldehyde resins can be mixed with water better, fast curing speed, and there is also a good bonding strength. Research and development of new urea-formaldehyde resin production process with a lower content of free formaldehyde is also a more realistic road, although many results, but still not fundamentally shake the position of urea-formaldehyde resin in the adhesive.